BLM and Antifa normally work side by side. They are both communist. It was only when antifa was getting shut down and found out so badly that BLM started to go a different way. Largely they where welcome though at each others events. This was more of a communism thing then anything else is the reality of what was going on in this aspect.
I believe there was actual movement but then they where found out and psyop started to take place to see where it was going in this way.
So we will see what happens maybe I am wrong maybe I am not.